Adjuvant activity of alum adjuvant and MF59 for HIV-1 multi-epitope protein MEP1

Abstract

Objective To compare the adjuvant activity of oil-in-water emulsion MF59 and aluminum hydroxide on immune responses to HIV-1 multi-epitope protein MEP1 in BALB/c mice. Methods HIV-1 multi-epitope protein MEP1 with MF59 or aluminum was prepared to intramuscularly vaccinate female BALB/c mice for three times. Serum and splenocytes were isolated from the mice 10 d after the first and last vaccination. Specific anti-MEP1 antibodies and the subclasses in serum were detected by ELISA. The numbers of splenic lymphocytes secreting IFN-γ and IL-4 were measured by ELISPOT. Differences in humoral and cellular immune responses induced by the two different adjuvants were compared. Results After a single-dose immunization, aluminum adjuvant promoted early humoral and cellular immune responses to MEP1 compared with MF59. After the three-dose immunization, both aluminum adjuvant and MF59 promoted MEP1 to induce Th2-biased humoral immune response, while MF59 also enhanced a balanced Th1/Th2 cellular immune response. Conclusions Aluminum adjuvant was a more suitable adjuvant than MF59 for HIV-1 multi-epitope protein MEP1. Key words: MF59; Aluminum adjuvant; Protein vaccine; Cytokine; Antibody